Grass Valley in the early 1900s was a metallic medley of thundering stamp mills, roaring furnaces, hammers, horse-drawn carriages and new-fangled cars. Empire Mine was in operation 24/7. Under the supervision of George Starr, the mine was thriving — and enjoying its reputation as one of the largest, most prosperous hard-rock gold mines in North America. Empire Mine State Historic Park docent Vince Seck has portrayed Starr for over 15 years. Visitors often meet him in the grease grit of the mine yard or welcoming guests to elegant Bourn Cottage. “George Starr was both a hands-on leader and a sociable …